In the blood drawing devices disclosed in Hollister U.S. Pat. Nos. 5,139,489 and 5,154,285, a Vacutainer holder has fitted thereto a pivotable housing for covering a contaminated cannula of a double-ended needle that is threaded to the Vacutainer holder. The disclosures of the '489 and '285 patents are incorporated by reference herein. Although work well, the devices of the '489 and '285 patents require that the user thread a double-ended needle assembly to the Vacutainer holder before use. For the user to thread the double-ended needle assembly to the Vacutainer holder, the protective cap that keeps the double-ended needle sterile needs to be removed first. Accordingly, even before the device is used, there is the problem that the end of the double-ended needle assembly that fits into the Vacutainer holder may become non-sterile. So, too, given the fact that the Vacutainer holder is shipped without any protection, the inside of the holder is non-sterile to begin with.
Furthermore, for those Vacutainer holders that do not have the protective housing disclosed in the '489 and '285 patents, a phlebotomist tends to reuse the Vacutainer holder for drawing blood from multiple patients. To wit, once a double-ended needle assembly that has been threaded into the Vacutainer holder is contaminated, the phlebotomist will unthread the contaminated needle assembly and discard the same. A new double-ended assembly is then threaded into the same Vacutainer holder, so as to be used for the next patient. As a consequence, cross-contamination may occur at the inside of the Vacutainer holder, as blood collected from the earlier patient may have been splattered to the inside of the Vacutainer holder, so that blood collected from a later patient may be contaminated by the earlier drawn blood.